The border counties of Dane (now Christian), Logan and Menard were created by legislative acts, approved February 15, 1839. Shortly after this time the present irregular limits of Sangamon county were defined and its area determined by survey. It contains 875 square miles, or about 550,000 acres of land. Most of this was then virgin prairie, but there are many belts of timber along the Sangamon river and the various creeks that flow into it. The greatest length of the county from east to west is near forty-one miles, and its extreme breadth some thirty-two miles. It is bounded on the north by Logan and Menard; on the west and northwest by Morgan and Cass; on the south by Macoupin and Montgomery; on the southeast by Christian, and on the east by Macon county.

At a meeting of the board of justices in June 1860, a petition was presented, praying that the question of township organization under the general act of 1851 be submitted to the voters of Sangamon county. The question was accordingly submitted at the regular election held on November 6. 1860, and it was carried by a majority of votes, out of a total vote of 7,241. At the meeting of the board of justices in December, following, John S. Bradford, John Gardner Sr., and Joseph Campbell were appointed a committee to divide the county into townships, in accordance with the general law on the subject. On March 1, 1861, this committee submitted to the county board their report in writing, which was approved. By it the county was divide into twenty-two townships, hearing the following names: Auburn, Ball, Buffalo Hart, Campbell (now Chatham, Clear Lake, Cooper, Cotton Hill, Curran, Gardner, Illiopolis, Island Grove, Loami, Mechanicsburg, Pawnee, Power (now Fancy Creek), Rochester, Sackett (now Salisbury), Spr ingfield, Talkington, Williams, and Woodside.